1. Field of the Invention
The invention relates to a high-speed current switch, and particularly to such a switch that does not require an external bias-voltage source.
2. Description of Related Art
European Patent Application 722221, published on Jul. 17 1996, describes a high-speed current switch that needs no external bias source for transistors in the switch. As described in that patent, an external reference bias source with a low output impedance had been used in prior art current switches for rapidly charging and discharging intrinsic capacitances in the current switch, thereby decreasing the settling time of the switched current. This increases the cost of the switch and, in integrated circuit implementations, also increases the number and complexity of conductors that must be provided for external connections. European Patent Application 722221 proposes relatively simple current-switch circuitry that does not require such an external bias source.